Cyclone Idai, the storm that battered cities, submerged homes and potentially killed hundreds of people in southeastern Africa, may prove to be one of the worst weather-related disasters ever in the Southern Hemisphere, a United Nations official said on Tuesday.
Officials with global aid groups and in Mozambique, where the storm hit hardest, are only beginning to reckon with its destruction. Potentially 1.7 million people were in the direct path of the cyclone, the United Nations estimated on Tuesday, and rain is forecast to continue in parts of the region for several days.
Herve Verhoosel, a spokesman for the United Nations World Food Program, said in an interview that the agency’s workers had described seeing “water and water for miles and miles” — flooding so severe it resembled an inland ocean where homes and towns had stood.
The situation remained dire, he said, for potentially hundreds of thousands of people in need of food, clean water and evacuation.
Cyclone Idai made landfall last Thursday into Friday on the coast of Southeast Africa, striking Mozambique, Malawi and Zimbabwe. (Like hurricanes and typhoons, a cyclone is a low-pressure circular storm system with winds greater than 74 miles per hour, each termed according to where it forms.)
Mr. Verhoosel said that some aid workers were sent to Mozambique before the storm landed to prepare to help assess the damage, and that it quickly became clear that they would need more help. The rainfall caused rivers to burst over their banks and submerged city streets and homes.
In addition to the 1.7 million people potentially affected in Mozambique, the World Food Program estimated that 920,000 people were affected in Malawi and 15,000 in Zimbabwe.
Because of the flooding, most roads and bridges are closed, and many regions have no power — shutting down communications and airports that could be used to bring in supplies and evacuate people. Mr. Verhoosel said that people were stranded on rooftops and climbing into trees to escape the water, and were without food, safe water or medicine.
The scale of the destruction
In Beira, one of Mozambique’s major port cities, Jamie LeSueur, an emergency operations manager for the International Federation of Red Cross and Red Crescent Societies, said, “It seems that 90 percent of the area is completely destroyed.”
“The situation is terrible. The scale of devastation is enormous,” he said in a statement on Monday. “Communication lines have been completely cut and roads have been destroyed. Some affected communities are not accessible.”
He added that it could be worse outside the city, saying, “Yesterday, a large dam burst and cut off the last road to the city.”
Aerial assessment of the Buzi Valley, west of Beira and along the Buzi River, “showed entire villages wiped out,” the World Food Program said in a statement.
At a news conference on Tuesday, Matthew Cochrane, a spokesman for the I.F.R.C., said that flooding could be as deep as six meters, covering roofs, palm trees and telephone poles.
Mr. Verhoosel said the death toll in Mozambique, which stood at 84 on Monday, was expected to climb into the hundreds. President Filipe Nyusi of Mozambique reportedly said the death toll could surpass 1,000.
“If these reports, these fears, are realized, then we can say that this is one of the worst weather-related disasters — tropical cyclone-related disasters — in the Southern Hemisphere,” said Clare Nullis, a spokeswoman for the World Meteorological Organization, citing the president’s figure.
What’s being done
So far, boats and helicopters have been the primary method of rescuing people and distributing aid, Mr. Verhoosel said. Planes have only recently been able to fly again over regions of Mozambique because of the weather.
He said at a news conference Tuesday that the pilots had been “incredible,” flying into airports “damaged by the water, dark with no light or radio communication with the control tower.”
The first cargo plane had arrived with 20 tons of food this weekend, he said, “but that’s not enough — we need much, much more.” The World Food Program said it would try to help 600,000 people in Mozambique by bringing in corn, beans, blankets, water and other supplies.
The agency’s warehouse in Beira was itself badly damaged, but some food survived, and the agency is sheltering people at 18 schools and churches across the city.
Christian Lindmeier, a spokesman for the World Health Organization, said the agency was trying to distribute emergency health kits and cholera kits.
What can you do to help
Mr. Verhoosel urged people to donate to the World Food Program and the International Federation of Red Cross and Red Crescent Societies, saying that they were in need.